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intellevation |
intellemetrics™
Optical
Monitoring For Plasma Etch & Thin Film Coating |
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PRODUCTS Crystal Monitors |
Quartz
Crystals
Crystal Prices All crystals are 14mm diameter and provided in rotary dispensers in quantities of ten.All crystals are AT-cut and low thermal coefficient.
Postage & Handling The prices shown below are fixed for 1 to 10 packets (See Minimum Order Quantity below), i.e. they are independent of the number of packets ordered.
Ordering Instructions All prices given above are excluding VAT or other duties that may be applicable. Therefore total price = ( Pack of 10 Price x Number of Packs ) + Postage & Handling + VAT if applicable.
Parties wishing to purchase crystals should email a valid Purchase Order to enquiries-crystals@intellevation.co.uk or fax it to +44 (0)141 882 9223. Parties who already have trading accounts with Intellevation will have goods despatched as soon as available and will receive an invoice within 30 days. Parties who do not
have a trading account with Intellevation will be required to make full
payment before goods are despatched. Notes on Extending Crystal Life A very general and approximate guide figure for the thickness at which a quartz crystal will fail is 30um. The crystal fails when the accumulation of deposited layers peel off under stress. The stress becomes higher as the layers build up and is further increased if several different materials are deposited on one crystal. Interlayer stress is increased if multiple materials are deposited on the crystal. Interlayer stress is much higher for some materials such as magnesium fluoride (MgF) which leads to short crystal life. Intellevation can provide alloy coated crystals which reduce the stress between the crystal and the first deposited layer of MgF. Customers have observed an increase in crystal life by a factor of 2.5 when changing from gold or silver coated crystals to alloy coated crystals. Crystal life can be extended by placing the crystal further away from the source but this also reduces sensitivity as less evaporant falls on it. The Intellemetrics IL820 has a feature called sample and hold described in the manual. A single crystal shuttered head is required. Sample and hold is suitable for a process with stable evaporation rates and saves the crystal by only looking at the source for long enough to bring the rate under control and then closing the shutter for a while. When the shutter is closed, the IL820 extrapolates the thickness and holds the source power constant until the next sampling period when the rate can again be adjusted. Double crystal sensor heads are also available. The second crystal is left covered and therefore provides a standby should the first crystal fail, thus avoiding losses due to failure during a run. For the most accurate thickness readings or the finest rate control, a fresh crystal should be used for each deposition run. This is required when one is approaching the limit of the resolution of the IL820 instrument which is 0.001nm and 0.001nm/second. |
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Copyright
© Intellevation
Ltd 2006 |
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